Method for generating color conversion information, color conversion information generation program, and color conversion information generation device

1. A method for generating color conversion information comprising causing a computer to execute: an acceptance step of accepting first information prescribing a first color in a first color space and second information prescribing a second color in the first color space; a first generation step of generating one or a plurality of intermediate points located on a first line segment connecting a first coordinate value representing the first color in the first color space and a second coordinate value representing the second color in the first color space, based on a plurality of reference points arranged in a grid-like form in the first color space; a first conversion step of converting the first coordinate value into a first converted coordinate value in a second color space, using first conversion information for converting a coordinate value in the first color space into a coordinate value in the second color space, and converting the second coordinate value into a second converted coordinate value in the second color space, using the first conversion information; a setting step of setting a first adjustment value in such a way that a first output device outputting an image corresponding to a coordinate value in the second color space outputs the first color according to a coordinate value resulting from adjusting the first converted coordinate value by the first adjustment value, and setting a second adjustment value in such a way that the first output device outputs the second color according to a coordinate value resulting from adjusting the second converted coordinate value by the second adjustment value; a specification step of specifying a third adjustment value used when the first output device performs an output corresponding to a coordinate value resulting from adjusting a third converted coordinate value converted from a third coordinate value in the first color space representing the intermediate point by the first conversion information, based on the first adjustment value and the second adjustment value; a second generation step of generating modified conversion information for converting a coordinate value in the first color space into a coordinate value in the second color space, based on the first conversion information; a third generation step of generating a fourth coordinate value located on the first line segment, based on an operation by a user; and a fourth generation step of generating color conversion information for converting the first information into a fifth coordinate value in the second color space, converting the second information into a sixth coordinate value in the second color space, and converting information about the fourth coordinate value into a seventh coordinate value in the second color space, based on the modified conversion information, the first generation step including generating one or a plurality of the intermediate points in such a way that a number of the intermediate points corresponding to the plurality of reference points is one or fewer, the second generation step including generating the modified conversion information in such a way that, when a coordinate value on the first line segment is converted into a coordinate value in the second color space by the modified conversion information, the coordinate value resulting from the conversion reflects one of the first adjustment value, the second adjustment value, and the third adjustment value.

2. The method for generating color conversion information according to claim 1 , wherein the setting step includes: causing a color measurement device to measure a color of an output image outputted from the first output device according to the first converted coordinate value, and acquiring a result of the measuring as a measured color coordinate value in the first color space; converting the first converted coordinate value into a fourth converted coordinate value in the first color space, using second conversion information for converting a coordinate value in the second color space into a coordinate value in the first color space; deciding a target coordinate value in the first color space, based on a difference between the first coordinate value and the measured color coordinate value, and on the fourth converted coordinate value; searching for a fifth converted coordinate value that satisfies a condition that a color difference between a sixth converted coordinate value in the first color space converted from the fifth converted coordinate value in the second color space, using the second conversion information, and the target coordinate value, is smaller than a color difference between the fourth converted coordinate value and the target coordinate value; and setting a difference between the fifth converted coordinate value and the first converted coordinate value, as the first adjustment value.

3. The method for generating color conversion information according to claim 1 , wherein the third generation step includes: accepting a number of the fourth coordinate values to be generated, in response to an operation by the user; and generating coordinate values in the number equally dividing the first line segment by a number greater than the number by 1, as the fourth coordinate values.

4. The method for generating color conversion information according to claim 1 , wherein the specification step includes: interpolating the third adjustment value corresponding to the third coordinate value, based on the first adjustment value corresponding to the first coordinate value and the second adjustment value corresponding to the second coordinate value, and thus specifying the third adjustment value.

5. The method for generating color conversion information according to claim 1 , further comprising causing the computer to execute: a second conversion step of, when image information included in an output command supplied to the first output device represents a color-gradient image successively changing in color according to a position from one end of the image to the other end, converting information about a coordinate value in the first color space corresponding to a position in the color-gradient image into a coordinate value in the second color space, using the color conversion information; and an output control step of causing the first output device to output a color corresponding to the position, according to the coordinate value in the second color space converted by the second conversion step.

6. The method for generating color conversion information according to claim 5 , wherein the output control step includes: when an output command including image information representing a color-gradient image successively changing in color according to a position from one end of the image to the other end is supplied to a second output device outputting an image corresponding to a coordinate value in the second color space, causing the second output device to output a color corresponding to a position in the color-gradient image, according to a coordinate value in the second color space resulting from converting information about a coordinate value in the first color space corresponding to the position in the color-gradient image by the second conversion step.

7. The method for generating color conversion information according to claim 6 , further comprising: a third conversion step of converting the coordinate value in the second color space converted by the second conversion step, into a correction value, using calibration color conversion information representing a correspondence between a coordinate value in the second color space and a correction value that causes a color of an image outputted from the second output device according to the coordinate value to be closer to a color of an image outputted from the first output device, wherein the output control step includes causing the second output device to output the color corresponding to the position according to the correction value converted by the third conversion step.

8. A non-transitory computer-readable storage medium storing a color conversion information generation program, the program causing a computer to function as: an acceptance unit accepting first information prescribing a first color in a first color space and second information prescribing a second color in the first color space; a first generation unit generating one or a plurality of intermediate points located on a first line segment connecting a first coordinate value representing the first color in the first color space and a second coordinate value representing the second color in the first color space, based on a plurality of reference points arranged in a grid-like form in the first color space; a first conversion unit converting the first coordinate value into a first converted coordinate value in a second color space, using first conversion information for converting a coordinate value in the first color space into a coordinate value in the second color space, and converting the second coordinate value into a second converted coordinate value in the second color space, using the first conversion information; a setting unit setting a first adjustment value in such a way that a first output device outputting an image corresponding to a coordinate value in the second color space outputs the first color according to a coordinate value resulting from adjusting the first converted coordinate value by the first adjustment value, and setting a second adjustment value in such a way that the first output device outputs the second color according to a coordinate value resulting from adjusting the second converted coordinate value by the second adjustment value; a specification unit specifying a third adjustment value used when the first output device performs an output corresponding to a coordinate value resulting from adjusting a third converted coordinate value converted from a third coordinate value in the first color space representing the intermediate point by the first conversion information, based on the first adjustment value and the second adjustment value; a second generation unit generating modified conversion information for converting a coordinate value in the first color space into a coordinate value in the second color space, based on the first conversion information; a third generation unit generating a fourth coordinate value located on the first line segment, based on an operation by a user; and a fourth generation unit generating color conversion information for converting the first information into a fifth coordinate value in the second color space, converting the second information into a sixth coordinate value in the second color space, and converting information about the fourth coordinate value into a seventh coordinate value in the second color space, based on the modified conversion information, the first generation unit generating one or a plurality of the intermediate points in such a way that a number of the intermediate points corresponding to the plurality of reference points is one or fewer, the second generation unit generating the modified conversion information in such a way that, when a coordinate value on the first line segment is converted into a coordinate value in the second color space by the modified conversion information, the coordinate value resulting from the conversion reflects one of the first adjustment value, the second adjustment value, and the third adjustment value.

9. A color conversion information generation device comprising: an acceptance unit accepting first information prescribing a first color in a first color space and second information prescribing a second color in the first color space; a first generation unit generating one or a plurality of intermediate points located on a first line segment connecting a first coordinate value representing the first color in the first color space and a second coordinate value representing the second color in the first color space, based on a plurality of reference points arranged in a grid-like form in the first color space; a first conversion unit converting the first coordinate value into a first converted coordinate value in a second color space, using first conversion information for converting a coordinate value in the first color space into a coordinate value in the second color space, and converting the second coordinate value into a second converted coordinate value in the second color space, using the first conversion information; a setting unit setting a first adjustment value in such a way that a first output device outputting an image corresponding to a coordinate value in the second color space outputs the first color according to a coordinate value resulting from adjusting the first converted coordinate value by the first adjustment value, and setting a second adjustment value in such a way that the first output device outputs the second color according to a coordinate value resulting from adjusting the second converted coordinate value by the second adjustment value; a specification unit specifying a third adjustment value used when the first output device performs an output corresponding to a coordinate value resulting from adjusting a third converted coordinate value converted from a third coordinate value in the first color space representing the intermediate point by the first conversion information, based on the first adjustment value and the second adjustment value; a second generation unit generating modified conversion information for converting a coordinate value in the first color space into a coordinate value in the second color space, based on the first conversion information; a third generation unit generating a fourth coordinate value located on the first line segment, based on an operation by a user; and a fourth generation unit generating color conversion information for converting the first information into a fifth coordinate value in the second color space, converting the second information into a sixth coordinate value in the second color space, and converting information about the fourth coordinate value into a seventh coordinate value in the second color space, based on the modified conversion information, the first generation unit generating one or a plurality of the intermediate points in such a way that a number of the intermediate points corresponding to the plurality of reference points is one or fewer, the second generation unit generating the modified conversion information in such a way that, when a coordinate value on the first line segment is converted into a coordinate value in the second color space by the modified conversion information, the coordinate value resulting from the conversion reflects one of the first adjustment value, the second adjustment value, and the third adjustment value.